Derailleur

Abstract

A derailleur 10 , for moving a chain 60 to different sized sprockets arranged small to large in a sprocket nest 101 is disclosed. The derailleur 10 has a pivot guide feed arm 11 for directing the chain 60 onto one of multiple sprockets within the sprocket nest 101 . The pivot guide feed arm 11 is rotatably mounted at a pivot end on an angular pivot pin 12 and when the pivot guide feed arm 11 rotates about the pivot pin 12 an opposite chain guide end of the pivot guide feed arm 11 traces a path substantially parallel to a tangent to the outer periphery of the sprocket nest 101 . The movement of the pivot guide feed arm 11 is mechanically driven by a user command and is preferably moved by a connected rod or wire or cable 109.

The invention claimed is: 
     
       1. A derailleur for moving a chain to different sized sprockets arranged between a range of sizes increasing from smallest to largest in a sprocket nest, the derailleur comprises:
 an angled pivot guide feed arm for directing the chain onto one of multiple sprockets within the sprocket nest, wherein the angled pivot guide feed arm is rotatably mounted over pivot end on a single angular pivot pin fixed on an inclined surface attached to a frame, the inclined surface being oriented at an angle equal to a tangent slope of the sprocket nest as measured by a straight line formed between the largest sprocket and the smallest sprocket and when the angled pivot guide feed arm pivot end rotates about the pivot pin, an opposite upper chain guide end of the angled pivot guide feed arm supports a chain guide roller and traces a fixed planar arcuate path along a sweep angle set and controlled by the rotation about said singular angular pivot pin; 
 a chain slack take-up idler arm having a pair of take-up frame sides, the chain slack take-up idler arm for chain slack take-up being pivotally connected to the upper chain guide end of the angled pivot guide feed arm and extending to a chain take up roller at a bottom opposite end of the chain slack take up idler arm, both the chain guide roller and the chain take-up rollers being held between the take-up frame sides of the chain slack take-up idler arm; and, 
 wherein the angled guide feed arm and the pivotally connected chain slack take-up idler arm use the chain guide roller at the upper end to both direct the chain onto one of the sprockets and to take up chain slack at the chain slack idler arm, when the chain slack take-up idler arm is moved centered on a middle sprocket the chain guide roller and the chain take up roller are both aligned parallel and in the same plane with the middle sprocket of the sprocket nest wherein the chain slack take-up idler arm when moved from alignment with the middle sprocket is canted on an angle at either extremes of the smallest and largest sprockets wherein the chain guide roller and chain take-up roller are not aligned parallel and in the same plane relative to the respective smallest or largest sprocket creating a twist in the chain which is straightened out by a movement of the guide roller and chain take-up roller by utilizing a gap or clearance between the take-up frame sides of the chain slack idler arm. 
 
     
     
       2. The derailleur of  claim 1  wherein movement of the pivot guide feed arm is mechanically driven by a user command. 
     
     
       3. The derailleur of  claim 1  wherein the movement of the pivot guide feed arm is moved by a connected cable or rod or wire. 
     
     
       4. The derailleur of  claim 1  wherein the chain guide roller is a toothed roller. 
     
     
       5. The derailleur of  claim 1  wherein the angled pivot guide feed arm and chain slack take-up idler arm are both spring loaded by a single spring. 
     
     
       6. The derailleur of  claim 1  wherein the angled pivot guide feed arm and chain slack take-up idler arm share a single spring, the single spring being connected to the pivotal guide feed arm and the chain slack take-up idler arm. 
     
     
       7. The derailleur of  claim 6  wherein the spring biases both the pivot guide feed arm and chain slack take-up idler arm. 
     
     
       8. The derailleur of  claim 7  wherein one end of the spring is connected to the angled pivot guide feed arm near the pivot end and the opposite end of the spring is connected to the chain slack take-up idler arm biasing the chain slack take-up idler arm to provide the chain slack take-up. 
     
     
       9. The derailleur of  claim 1  wherein the chain slack take-up idler arm lies within a space between the driver sprocket and driven sprocket nest, the space defined as the area between the major diameter sprocket of the driver sprocket and driven sprockets wherein the entire derailleur is located in the space defined by an upper line and a lower line drawn between the major diameters of the largest or major sprocket of the sprocket nest and the major diameter of the forward drive sprocket. 
     
     
       10. The derailleur of  claim 1  wherein a distance of at least 10 inches is provided between the drive sprocket and the driven sprocket nest. 
     
     
       11. The derailleur of  claim 1  wherein the nested and stacked rear sprocket nest having multiple sprocket gears is combined with a multiple forward drive sprocket nest having multiple sprocket gears and the derailleur is capable of changing both the rear gears and the forward gears by moving the chain at both locations using the one derailleur. 
     
     
       12. A derailleur for moving a chain to different sized sprockets arranged between a range of sizes increasing from smallest to largest in a sprocket nest, the derailleur comprises:
 an angled pivot guide feed arm supporting a chain guide roller for directing the chain onto one of multiple sprockets within the sprocket nest, 
 wherein the angled pivot guide feed arm is rotatably mounted over pivot end on a single angular pivot pin fixed on an inclined surface attached to the frame, the inclined surface being oriented at an angle equal to a tangent slope of the sprocket nest as measured by a straight line formed between the largest sprocket and the smallest sprocket and when the angled pivot guide feed arm pivot end rotates about the pivot pin, an opposite upper chain guide end supporting the chain guide roller of the pivot guide feed arm traces a planar arcuate path along a sweep angle set and controlled by the rotation about said singular angular pivot pin; 
 a projection about or near the pivot end, wherein coils of a tension spring rest on the projection and prevent or limit the tension spring coils from reaching the center of rotation and the tension spring biases both the angled pivot guide feed arm and a chain slack take up idler arm having a chain take up roller and a pair of take-up frame sides, the tension spring being connected to the angled pivotal guide feed arm and the chain slack take-up idler arm, both the guide roller and the chain take-up rollers being held between the take up frame sides of the chain slack take-up idler arm; and 
 wherein when the chain slack take-up idler arm is moved centered on a middle sprocket the chain guide roller and the chain take up roller are both aligned parallel and in the same plane with the middle sprocket of the sprocket nest wherein the chain slack take-up idler arm when moved from alignment with the middle sprocket is canted on an angle at either extremes of the smallest and largest sprockets wherein the chain guide roller and chain take-up roller are not aligned parallel and in the same plane relative to the respective smallest or largest sprocket creating a twist in the chain which is straightened out by a movement of the guide roller and chain take-up roller by utilizing a gap or clearance between the take-up frame sides of the chain slack idler arm. 
 
     
     
       13. A derailleur for moving a chain to different sized sprockets arranged between a range of sizes increasing from smallest to largest in a sprocket nest, the derailleur comprises:
 an angled pivot guide feed arm bent supporting a chain guide roller for directing the chain onto one of multiple sprockets within the sprocket nest, 
 wherein the angled pivot guide feed arm is rotatably mounted over pivot end on a single angular pivot pin fixed on a frame or on an inclined surface attached to the frame, the inclined surface being oriented at an angle equal to the tangent slope of the sprocket nest as measured by a straight line formed between the largest sprocket and the smallest sprocket and when the angled pivot guide feed arm pivot end rotates about the pivot pin, an opposite upper chain guide end supporting the chain guide roller of the pivot guide feed arm traces a fixed planar arcuate path along a sweep angle set and controlled by the rotation about said singular angular pivot pin; 
 a single tension spring biasing the pivot guide feed arm, the tension spring being connected to the twisted pivot guide feed arm at or near the pivot end and to a chain slack take-up idler arm having a chain take up roller; 
 a lancing segment of sheet metal adjacent a hub or pivot to support the tension spring smoothly against the side coils of the spring; and 
 wherein when the chain slack take-up idler arm is moved centered on a middle sprocket the chain guide roller and the chain take up roller are both aligned parallel and in the same plane with the middle sprocket of the sprocket nest wherein the chain slack take-up idler arm when moved from alignment with the middle sprocket is canted on an angle at either extremes of the smallest and largest sprockets wherein the chain guide roller and chain take-up roller are not aligned parallel and in the same plane relative to the respective smallest or largest sprocket creating a twist in the chain which is straightened out by the movement of the guide roller and chain take-up roller by utilizing a gap or clearance between the take-up frame sides of the chain slack idler arm. 
 
     
     
       14. The derailleur of  claim 13  further comprises:
 a tension spring swivel connector built as a tube or pin to prevent an end loop of the spring from falling off.